Electric guitars are often fitted with mechanisms for dynamically changing the tension upon one or more of the sound-producing strings, so as to vary the pitch. By using such a mechanism to alternately change tension on the strings, a so-called "tremolo" effect can be produced; reducing the tension from the as-tuned condition results in what is known as a "choking" effect; "not bending" and "detuning" effects can be produced as well with mechanisms of this type.
In their most conventional form, tremolo devices employ a lever which is pivotably mounted on the bridge block, at a location adjacent the bass E-string of a guitar (i.e., nearer the lower edge of the instrument body in normal playing position), and is disposed to the front of the body near its tail or bottom end; thus, it is positioned for oscillation by the player using his picking and strumming hand. The produce the desired effect, the performer must therefore first play a note or chord, and then move his hand to operate the tremolo lever or bar; he cannot readily do both at the same time.
Variations in the means for operating pitch varying mechanisms of this type have been proposed in the art. For example, in Glaser, II U.S. Pat. No. 4,354,417, a tone changer unit is disclosed wherein individual strings may be attached to one of three lever arms to enable alteration of their pitch. An extension arm is non-rotatably connected to one of the three lever arms, and is designed to be operated by engagement with the performer's body. The unit is located at the top of the instrument body near the neck junction, and cables are employed to transmit movement of the operating lever assembly to the bridge assembly, and thereby to the strings of the instrument.
A note bender attachment is shown in Borisoff U.S. Pat. No. 4,535,670, which is actuated by body movements through contact with an arm that extends rearwardly from the tail end of the instrument. The actuating arm is evidently disposed to lie alongside of the player's hip when the instrument is held in playing position.
Other United States patents show pitch changing devices for stringed instruments which are actuated in various ways. Thus, Lohman U.S. Pat. No. 2,136,627 uses an electric motor to vibrate the bridge of a guitar, and U.S. Pat. No. 3,382,749 to Watson discloses the similar use of the pneumatic diaphragm. A pedal-operated tuning control arrangement, which is connected from the rear of the instrument, is shown in Jurichek U.S. Pat. No. 2,889,732, and strap-control mechanisms are disclosed both in Parson et al U.S. Pat. No. 3,512,443 and in Fender U.S. Pat. No. 3,686,993.
Kusakawa U.S. Pat. No. 3,910,152 provides a sliding bridge for a stringed instrument, the position of which may be adjusted by pedals connected through the rear of the body. Lundquist U.S. Pat. No. 4,343,220 utilizes the chin rest of a violin, or a chest or hand-operated plunger arrangement, to produce vibrato by oscillation of the bridge, and an external frame is described by Carson in U.S. Pat. No. 4,397,212 for producing vibrator and pitch control in a guitar.
Although the prior art therefore discloses different forms of hand-held stringed musical instruments having dynamic pitch changing mechanisms, which are operated by movement of the instrument relative to the player's body, still the arrangements disclosed are not optimal. The performing styles of modern guitarists are often typified by wide-ranging and vigorous movement, and may be inhibited to the extent that such action is dictated by the need to maintain the operating member, of a pitch-controlling mechanism for the instrument, in a certain position. The musical, as well as the visual, quality of the performance may be significantly affected as a result.
Hennessey U.S. Pat. No. 4,658,693 provides apparatus for dynamic pitch variation in a hand-held stringed musical instrument, and an instrument incorporating such apparatus, which permits the performer to effectively control the character of the sound produced while, at the same time, affording him a wide range of movement. This is achieved by pivotably attaching an operating arm to the bridge block, in such a manner as to dispose the arm along the rear face of the body of the instrument.
Despite the highly effective and desirable nature of the device of the Hennessey patent, a demand remains for a pivotable bridge block assembly in which a rear-mounted operating arm can be extended and retracted from the front of the instrument, so as to permit the player to quickly, easily and selectively condition for use, or effectively disable, the pivot-actuating structure. It is important moreover, that the device be so designed that the instrument can be rested against the performer's body, with the bridge-pivoting arm in its operative condition, without causing inadvertent shifting the block and thereby unwanted pitch changes.
Accordingly, it is the broad object of the present invention to provide a novel mechanism for a pivotable, musical instrument bridge block, wherein a rear mounted operating lever, used for pivoting of the block, can be moved between relatively operative and inoperative positions by manipulation of positioning means accessible at the front of the instrument.
Related objects are to provide a bridge block assembly, and a musical instrument, incorporating such a mechanism.
More specific objects of the invention are to provide a mechanism and assembly having the foregoing features and advantages, wherein the means provided for coupling the operating lever to the positioning means is particularly adapted for permitting rapid extension and retraction of the operating arm while, at the same time, positively affixing the arm in any selected position throughout its range of movement, and to provide an operating arm which is itself of variable orientation.
Another broad object of the invention is to provide a musical instrument having a rear-operated pivotable bridge block, in which the operating lever is so constructed and mounted that the instrument can be rested upon the performer's body without causing inadvertent changes of string pitch.
Further objects are to provide such a mechanism and assembly which are of relatively simple and inexpensive construction, which may readily be fitted to a musical instrument either as original equipment or as an add-on feature, for after-market installation, and which present a tremolo-producing lever on the front of the instrument, near the edge of the body that is upwardly disposed in normal playing position.